On Valentine's Day, 25-year-old Michael Schaab tied a box with an engagement ring inside around the neck of his excitable springer spaniel to propose to his girlfriend, Megan Shively.

Thursday afternoon, he took a lunch break from his job as a geriatric therapist at Western Psychiatric Institute and Clinic of UPMC to make a tuition payment on the occupational therapy graduate program he was due to start in June.

As he returned to work, Mr. Schaab was killed after he crossed the path of 30-year-old John Shick, who indiscriminately opened fire in the Western Psych lobby in an act of violence police have yet to understand. After fatally wounding Mr. Schaab and injuring several others, Mr. Shick himself was shot to death by University of Pittsburgh police.

It was a cruel coincidence for a family who experienced a similar loss less than two years ago. Mr. Schaab's sister Nancy was killed by her boyfriend, Jordan Just. Michael's parents, Mary and Harry, now will now have to bury their remaining child.

"Oh, we just don't believe this," said Lynn Daum, his aunt.

Friday, the grief-stricken family gathered at Ms. Daum's home in Monroeville, incredulous that such tragedy could strike them twice, taking a man so widely adored.

"He was just the nicest person, you can't even imagine," Ms. Shively said, still wearing the engagement ring he slipped on her finger when she said yes. The two were to be married next March at Heinz Chapel.

Raised in Greensburg, he was a Mario Brothers video game fanatic and was a goofy, sometimes precocious kid. In a favorite family photo, a young, scrawny Mr. Schaab is posing with a sarcastic smile and flexed biceps, donning a customized T-shirt printed with his school picture and "Chicks dig me" written beneath.

He attended Greensburg Central Catholic High School, where he excelled academically. He attended Robert Morris University, later transferred to Duquesne University and finally finished his degree in psychology at Pitt in 2008.

After graduation, he was hired by Western Psych as a therapist on the geriatric floor, leading group therapy for elderly patients and later ascending to leadership roles. Cool-headed and deeply empathetic, he was well-suited for the role and was respected by patients, their families and his colleagues alike, his fiancee said.

In a statement, Western Psych said he worked in program development and group therapy.

"It was clear that Michael was truly a leader among our staff, and he was beloved by the geriatric patients whom he cared for every day," Claudia Roth, the CEO of Western Psych, said in a statement. "Our thoughts and prayers are with his family and friends during this time. This senseless act of violence has had a profound impact on all of us who knew and admired him. He will be greatly missed."

Ms. Shively met Mr. Schaab in 2008 while she was a nursing student on a rotation at Western Psych. She observed his interactions with patients and called him "kind and patient."

"He stepped in with difficult patients," she said. "He was the one that would kind of calm everyone down."

Ms. Shively said Mr. Schaab found the work deeply satisfying. Little made him happier than when he felt he had made a measurable difference in a patient's life.

Outside of the hospital, his family said he tried to make everyone around him happy. Earlier this week, he picked up his fiancee from work and made her a pasta dinner -- even though he despises cooking.

He was close to his sister, his grandfather Art Daum said, but when she was killed he remained strong and served as an emotional bedrock for his family. He stayed with his aunt so that she would not have to be alone. And while others stewed with anger over her slaying, he tried to be "a more perfect son," Ms. Shively said.

Joe Daum, his uncle, said he believed part of his interest in psychology stemmed from his desire to better understand his sister, who struggled with psychological and drug problems. Mr. Schaab, like others in his family, blamed himself to some degree for her death at the hands of a volatile boyfriend, who was later convicted of voluntary manslaughter.

Working at Western Psych, "He could be an advocate for Nancy. He could walk in her shoes," Joe Daum said.

Visitation for Mr. Schaab will be held from 4 to 8 p.m. Sunday and from 2 to 4 p.m. and 6 to 8 p.m. Monday at the Bash-Nied Funeral Home, 152 Abbe Place in Delmont. A funeral Mass will be held at 11 a.m. Monday at St. John Baptist De La Salle Church, 497 Athena Drive in Delmont.